Newline possible in new search UI

Created by: eseliger

• Sourcegraph version: master
• Platform information: sourcegraph.com

Steps to reproduce:

1. Enter something in the search input
2. Hit cmd + return
3. See the feld "get cleared out" making me thing my query is gone
4. Navigate with arrow up
5. See query and realize it's a newline

Expected behavior:

No newline is inserted

Actual behavior:

It is and it might confuse people because the query still contains the first part